Diuncus justus (Schedl, 1931)

Smith, Sarah M., Beaver, Roger A. & Cognato, Anthony I., 2020, A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China, ZooKeys 983, pp. 1-442 : 1

Diuncus justus (Schedl, 1931) Fig. 50C, D, J

Xyleborus justus Schedl, 1931: 339.

Diuncus justus (Schedl): Hulcr and Cognato 2009: 32.

Xyleborus marginicollis Schedl, 1936c: 64. Synonymy: Hulcr 2010: 107.

Xyleborus ciliatus Eggers, 1940: 141. Synonymy: Hulcr and Cognato 2013: 81.

Xyleborus apiculatus Schedl, 1942a: 190. Synonymy: Hulcr and Cognato 2013: 81.

Type material.

Holotype Xyleborus justus (NMNH). Holotype Xyleborus marginicollis (NHMW).

New records.

Vietnam: Cao Bang, 22°34.5'N, 105°52.4'E, ~ 1080 m, 14.iv.2014, VN28, Cognato, Smith, Pham, ex Cunninghamia branches (MSUC, 1).

Diagnosis.

1.5-1.7 mm long (mean = 1.65 mm; n = 5); 2.36-2.5 × as long as wide. This species is distinguished by the minute size; unarmed declivity; declivital striae 1 shallowly impressed; nearly glabrous appearance; and lateral margin of the protibiae armed with four denticles.

Similar species.

Diuncus ciliatoformis .

Distribution.

Australia, China (Fujian), Indonesia (Java), East & West Malaysia, New Guinea, Vietnam*.

Host plants.

This species has only been recorded from Cunninghamia ( Cupressaceae ).

Remarks.

The synonymy of Xyleborus apiculatus , X. ciliatus , and X. marginicollis with Diuncus justus needs to be reassessed using information from DNA as well as morphology.

Figures

Figure 50. Dorsal, lateral and declivital view of Diuncus javanus, 2.5 - 2.7 mm (A, B, I), D. justus, 1.5 - 1.7 mm (C, D, J), D. mucronatulus holotype, 1.5 mm (E, F, K), and D. mucronatus, 2.0 - 2.5 mm (G, H, L).